How to make handlebars-loader used in conjunction with handlebars-helpers

Question

how the handlebars-loader to work with handlebars-helpers?

webpack.configs:

  { // handlebars-loader
    test: /\.handlebars$/,
    loader: "handlebars-loader?helperDirs[]=" + __dirname + "/helpers"
  }

but, how to import handlebars-helpers and use handlebars-helpers

thanks!